Bloom filter utilization for join processing

ABSTRACT

A computer-implemented method includes inserting a bloom filter creation stage after an inner data source identification stage, wherein a join operation is to be performed to join an outer data source with the inner data source. The method inserts a bloom filter search stage after an outer data source identification stage, wherein each row of data from the outer data source is searched against a bloom filter for the inner data source during the bloom filter search stage. The method initializes a read on the inner data source. Subsequent to determining the bloom filter creation stage is complete, the method initializes a read on the outer data source. The method performs the join operation at a join stage.

BACKGROUND

The present invention relates generally to join processing and moreparticularly to utilizing bloom filters in the join process of anExtract Transform Load.

Typically, Extract Transform Load (ETL) refers to a process in databaseusage, more specifically in data warehousing, performed by an ETL tool.The process includes extracting an original document from a source,transforming the data to fit operational needs, and loading thetransformed document into an end target (e.g., database or databasewarehouse). A join in an ETL process refers to combining a field fromtwo or more tables of data utilizing values common to each of thetables. Join processes in an ETL are typically time consuming sincethere are a number of I/Os being sent and received from external datalocations.

SUMMARY

Embodiments of the present invention disclose a method, computer programproduct and computer system for bloom filter utilization for joinprocessing. A computer-implemented method includes inserting, by one ormore processors, a bloom filter creation stage after an inner datasource identification stage, wherein a join operation is to be performedto join an outer data source with the inner data source; inserting, byone or more processors, a bloom filter search stage after an outer datasource identification stage, wherein each row of data from the outerdata source is searched against a bloom filter for the inner data sourceduring the bloom filter search stage; initializing, by one or moreprocessors, a read on the inner data source; subsequent to determiningthe bloom filter creation stage is complete, initializing, by one ormore processors, a read on the outer data source; and performing, by oneor more processors, the join operation at a join stage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional block diagram illustrating a distributed dataprocessing environment, in an embodiment in accordance with the presentinvention.

FIG. 2 is a flowchart depicting one embodiment of bloom filterutilization for staged reference data, in accordance with the presentinvention.

FIG. 3A is a flowchart depicting one embodiment of bloom filterutilization for non-staged reference data, in accordance with thepresent invention.

FIG. 3B is a flowchart depicting one embodiment of bloom filterutilization for non-staged reference data, in accordance with thepresent invention.

FIG. 3C is a flowchart depicting one embodiment of bloom filterutilization for non-staged reference data, in accordance with thepresent invention.

FIG. 4 is a block diagram of components of a computer system, such asthe computer server of FIG. 1, in an embodiment in accordance with thepresent invention.

DETAILED DESCRIPTION

Embodiments of present invention utilize bloom filters to accelerate theprocessing of joins in an ETL process. The present invention managesinstances where (i) the reference data (utilized in join) is staged and(ii) where the reference data is not staged. The present inventionallows for a cost based decision to manage a join workflow utilizingbloom filters. The join workflow utilizing bloom filters allows for areduction in I/O resources resulting in an increase in throughput and adecrease in system load.

Example embodiments in accordance with the present invention will now bedescribed in detail with reference to the drawing figures. FIG. 1 is afunctional block diagram illustrating a distributed data processingenvironment. The distributed data processing environment includes servercomputer 102 and client device 104 interconnected over network 106.

Server computer 102 may be a desktop computer, a laptop computer, atablet computer, a specialized computer server, a smartphone, or anyother computer system known in the art. In certain embodiments, servercomputer 102 represents a computer system utilizing clustered computersand components that act as a single pool of seamless resources whenaccessed through network 106, as is common in data centers and withcloud computing applications. In general, server computer 102 isrepresentative of any programmable electronic device or combination ofprogrammable electronic devices capable of executing machine readableprogram instructions and communicating with other computer devices via anetwork. In this embodiment, server computer 102 has the ability tocommunicate with other computer devices to query the computer devicesfor information.

Join optimizer 108 residing in server computer 102 utilizes bloom filter110 when managing joins in an Extract Transform and Load (ETL) process.Bloom filter 110 represents a probabilistic data structure, to testwhether an element is a member of a set. For example, join optimizer 108can utilize bloom filter 110 to determine if an element in outer datasource 116 is a member in another set, inner data source 114. Bloomfilter 110 produces one of two results for whether an element is amember of a set (i) an element is not a member of a set or (ii) anelement is possibly a member of a set. Join optimizer 108 has theability to generate and utilize bloom filter 110 utilizing statisticalmethods known in the art. In this embodiment, a data source for whichjoin optimizer 108 considers creating bloom filter 110 is referred to asinner data source 114 and a data source for which join optimizer 108searches against the bloom filter is referred to as outer data source116.

In one embodiment, join optimizer 108 can insert a bloom filter creationstage after inner data source 114 and a bloom filter search stage afterouter data source 116. Subsequent to the insertion of the bloom filter110 after inner data source 114, join optimizer 108 can initialize readsagainst the created bloom filter 110 to mitigate multiple fetches fordata. In another embodiment, join optimizer 108 can generate bloomfilter 110 based on reference data (i.e., inner data source 114) andinsert the bloom filter 110 after the source stage. Join optimizer 108can update the path of the inserted bloom filter in the inner datasetheader and determine if optimization conditions are satisfied forutilization of the bloom filter in the join. Subsequent to determiningthe optimization conditions are satisfied, join optimizer 108 can insertthe bloom filter after the outer source and perform the join of innerdata source 114 and outer data source 116.

Extract Transform and Load (ETL) engine 112 residing in server computer102 has the ability to receive source documents from multiple computerdevices not illustrated in FIG. 1. ETL engine 112 can transform thesource documents and load the transformed documents (i.e., targetdocuments) into a target storage location. Such a transformation, alsoreferred to as an ETL process, transforms the content of a sourcedocument (e.g., HTML to plain text) and stores the transformed contentin the form of a target document. ETL engine 112 can be a server-basedprogram. In this embodiment, ETL engine 112 is transforming data byjoining inner data source 114 and outer data source 116. ETL engine 112may communicate with or comprise of programs or tools such as, joinoptimizer 108.

Client device 104 may be a desktop computer, a laptop computer, a tabletcomputer, a specialized computer server, a smart phone, or anyprogrammable electronic device capable of communicating with servercomputer 102 via network 106. In general, client device 104 representsany programmable electronic device or combination of programmableelectronic devices capable of executing machine readable programinstructions and communicating with other computing devices via anetwork, such as network 106. Client device 104 includes user interface118 through which a user of client device 104 can communicate with ETLengine 112 residing on server computer 102.

User interface 118 provides an interface between client device 104, ETLengine 112, and join optimizer 108. User interface 118 may be agraphical user interface (GUI) or a web user interface (WUI) or acommand line interface and can display text, documents, web browserwindows, user options, application interfaces, and instructions foroperation, and includes the information (such as graphic, text, andsound) a program presents to a user and the control sequences the useremploys to control the program. User interface 118 may also be mobileapplication software that provides an interface between a user of clientdevice 104 and importation optimizer. Mobile application software, or an“app”, is a computer program designed to run on smart phones, tabletcomputers and other mobile devices. User interface 118 enables a user ofclient device 104 to establish administrative parameters for operationsthat ETL engine 112 and join optimizer 108 performs.

In general, network 106 can be any combination of connections andprotocols that will support communications among server computer 102 andclient device 104. Network 106 can include, for example, a local areanetwork (LAN), a wide area network (WAN), such as the internet, acellular network, or any combination of the preceding, and can furtherinclude wired, wireless, and/or fiber optic connections. In oneembodiment, join optimizer 108 can be a web service accessible vianetwork 106 to a user of client device 104. In another embodiment, joinoptimizer 108 may be operated directly by a user of server computer 102.

FIG. 2 is a flowchart depicting one embodiment of bloom filterutilization for staged reference data, in accordance with the presentinvention. As depicted the method includes generating (202) a bloomfilter based on the reference data, inserting (204) the bloom filterafter the source stage, updating (206) the path of the inserted bloomfilter in the inner dataset header, determining (208) if theoptimization conditions are satisfied, inserting (210) the bloom filterafter the outer data source identification stage, and performing (212)the join. In one embodiment, the bloom filter utilization is conductedby join optimizer 108.

The method may commence by generating (202) a bloom filter based on thereference data. In this embodiment, join optimizer 108 determines togenerate the bloom filter based on the reference data during the datasetcreation, where the inner data source represents the dataset beingcreated. The dataset creation represents a stage with a single outputlink, where a set of mock data fitting specified metadata is produced.The specified metadata represents metadata a user specifies on theoutput link which determines the columns of data being generated for theinner data source.

The method may continue by inserting (204) the bloom filter after thesource stage. In this embodiment, join optimizer 108 inserts the bloomfilter after the source stage in the dataset creation job. The methodmay continue by updating (206) the path of the inserted bloom filter inthe inner dataset header. In this embodiment, join optimizer 108 updatesthe inner dataset header for the inner data source with the path of theinserted bloom filter. By updating the inner data header for the innerdata source, the bloom filter is associated with the inner data sourceand join optimizer 108 can search the rows of the outer data sourceagainst the bloom filter.

The method may continue by determining (208) if the optimizationconditions are satisfied. In the event the optimization conditions aresatisfied (“yes” branch, 208), optimization program may continue byinserting (210) the bloom filter after the outer data sourceidentification stage. In the event the optimization conditions are notsatisfied (“no” branch, 208), join optimizer may continue by performing(212) the join, without utilizing the inserted bloom filter. Joinoptimizer 108 considers an optimization with bloom filters for a joinoperation on two different levels. The join operation has to satisfy thefollowing conditions, (i) the join operation should not have anyadditive stages between the inner data source and the join, (ii) joinkeys should pass through unmodified from the inner data source to thejoin, and (iii) join keys should pass through unmodified from the outerdata source to the join. Join keys representing a mapping of the columnand rows of the inner data source and outer data source.

Additionally, join optimizer 108 can include a rule for whether or notworkload characteristics for a specific join operation are met. Theworkload characteristics includes a determination of whether aprocessing cost of a specific join operation without a bloom filter isgreater than a processing cost of the specific join operation with thebloom filter. Below, Table 1 outlines an example for calculatingprocessing costs for the specific join operation with and without thebloom filter. The variables x, y, and z are computed for the hardwareprofiles, n₁ and n₂ are based on specific join operation, and r is basedon the data and filter configuration.

TABLE 1 Example Processing Cost Calculations Without Bloom Filter Cost =x * n₁ + y * n₂ With Bloom Filter Cost = x * n₁ ₊ x * n₂/r + y * n₁ +z * n₂ Where: n₁ = volume of dataset (i.e., inner data source)     n₂ =volume of database dataset (i.e., outer data source)     x = sort costper row     y = bloom filter creation cost per row     z = bloom filterprocessing cost per row     r = selectivity of bloom filter With BloomFilter Cost < Without Bloom Filter Cost x * n₁ ₊ x * n₂/r + y * n₁ + z *n₂ < x * n₁ + y * n₂ (i.e., y * n₁ ₊ z * n₂ < x * n₂ * (r − 1)/r)

The method may continue by inserting (210) the bloom filter after theouter data source identification stage. The bloom filter after the outerdata source identification stage represents the search stage where datain the outer data source is searched against the bloom filter of theinner data source. The method may continue by performing (212) the join.Subsequent to the insertion of the bloom filter, join optimizer canperform the join of the inner data source and outer data sourceutilizing the inserted bloom filter.

FIG. 3A is a flowchart depicting one embodiment of bloom filterutilization for non-staged reference data, in accordance with thepresent invention. As depicted the method includes, inserting (302)bloom filter creation stage after the inner data source identificationstage, inserting (304) bloom filter search stage after the outer datasource identification stage, initializing (306) read on the inner datasource, initializing (308) read on the outer data source subsequent tobloom filter creation, and performing (310) the join. In one embodiment,the bloom filter utilization is conducted by join optimizer 108.

The method may commence by inserting (302) bloom filter creation stageafter the inner data source identification stage. Since the inner datasource is not staged, join optimizer 108 inserts the bloom filtercreation stage downstream after the inner data source identificationstage but prior to the join operation in the ETL process. The method maycontinue by inserting (304) bloom filter search stage after the outerdata source identification stage, where data in the outer data source issearched against the bloom filter of the inner data source.

The method may continue by initializing (306) read on the inner datasource. The method may continue by initializing (308) read on the outerdata source subsequent to bloom filter creation. The completed creationof the bloom filter ensures all the rows of the outer data source aresearched against all the rows of the inner data source through thecompleted bloom filter. The method may continue by performing (310) thejoin. Subsequent to the insertion of the bloom filter, join optimizercan perform the join of the inner data source and outer data sourceutilizing the inserted bloom filter.

FIG. 3B is a flowchart depicting one embodiment of bloom filterutilization for non-staged reference data, in accordance with thepresent invention. As depicted the method includes, creating (312) aninner dataset from the inner data source and the associated bloomfilter, determining (314) if the creation of the inner dataset iscomplete, initializing (316) read on the outer data source, andperforming (318) the join. In one embodiment, the bloom filterutilization is conducted by join optimizer 108.

The method may commence by creating (312) an inner dataset from theinner data source and the associated bloom filter. In this embodiment,join optimizer 108 creates an inner dataset utilizing data from theinner data source and the associated bloom filter rather than utilizingdata being staged. Since the inner data source is non-staged data, joinoptimizer 108 can utilize the inner data source, apply the associatedbloom filter, and create the inner dataset.

The method may continue by determining (314) if the creation of theinner dataset is complete. In the event the creation of the innerdataset is complete (“yes” branch, 314), the method may continue byinitializing (314) read subsequent to bloom filter creation. In theevent the creation of the inner dataset is not complete, the method maycontinue by idling until the creation of the inner dataset is complete.The creation of the inner data set triggers the creation of the bloomfilter search stage after the outer data source identification stage.

The method may continue by initializing (316) read on the outer datasource. In this embodiment, join optimizer 108 performs theinitialization of the read subsequent to the creation of the bloomfilter by searching rows in the outer data source against the bloomfilter of the inner dataset. The method may continue by performing (318)the join. Subsequent to the insertion of the bloom filter, joinoptimizer can perform the join of the inner data source and outer datasource utilizing the inserted bloom filter.

FIG. 3C is a flowchart depicting one embodiment of bloom filterutilization for non-staged reference data, in accordance with thepresent invention. As depicted the method includes, inserting (320)bloom filter creation stage after the inner data source identificationstage, sending (322) rows from the inner data source to the join,inserting (324) bloom filter search stage after the outer data sourceidentification stage, determining (326) the bloom filter creation stageis complete, notifying (328) bloom filter search stage the bloom filtercreation stage is complete, loading (330) the bloom filter at the bloomfilter search stage, initializing (332) read of rows from the outer datasource against the bloom filter, and performing (334) the join. In oneembodiment, the bloom filter utilization is conducted by join optimizer108.

The method may commence by inserting (320) bloom filter creation stageafter the inner data source identification stage. Since the inner datasource is not staged, join optimizer 108 inserts the bloom filtercreation stage downstream after the inner data source identificationstage but prior to the join operation in the ETL process. The method maycontinue by sending (322) rows from the inner data source to the join.In this embodiment, join optimizer 108 sends rows from the inner datasource to the join stage of the ETL process prior to the bloom filtercreation stage being completed.

The method may continue by inserting (324) bloom filter search stageafter the outer data source identification stage. The bloom filtersearch stage operates in a non-blocking pass mode, where rows of dataare not searched against the bloom filter of the inner data sourcebecause it has not been completed yet. As a result, until the bloomfilter creation stage is completed, the rows from the outer data sourcepass through to the join stage of the ETL process.

The method may continue by determining (326) the bloom filter creationstage is complete. In this embodiment, an ETL engine can join the rowsfrom the outer data source and the rows from the inner data source untiljoin optimizer 108 determines the bloom filter creation stage iscomplete and rows being read from the outer data source can now besearched against the bloom filter.

The method may continue by notifying (328) bloom filter search stage thebloom filter creation stage is complete. With the notification, joinoptimizer 108 removes the non-blocking pass mode, where rows of data arenot searched against the bloom filter of the inner data source becauseit has not been completed yet. Instead, join optimizer 108 searches eachrow of the outer data source against the bloom filter of the inner datasource. The method may continue by loading (330) the bloom filter at thebloom filter search stage and initializing (332) read of rows from theouter data source against the bloom filter. As a result, rows from theinner data source no longer pass through to the join and rows from theouter data source are searched against the completed bloom filter at thecreation stage.

The method may continue by performing (334) the join. Subsequent to theinsertion of the bloom filter, join optimizer can perform the join ofthe inner data source and outer data source utilizing the inserted bloomfilter.

FIG. 4 depicts computer system 400, where server computer 102 is anexample of a system that includes join optimizer 108. The computersystem includes processors 401, cache 403, memory 402, persistentstorage 405, communications unit 407, input/output (I/O) interface(s)406 and communications fabric 404. Communications fabric 404 providescommunications between cache 403, memory 402, persistent storage 405,communications unit 407, and input/output (I/O) interface(s) 406.Communications fabric 404 can be implemented with any architecturedesigned for passing data and/or control information between processors(such as microprocessors, communications and network processors, etc.),system memory, peripheral devices, and any other hardware componentswithin a system. For example, communications fabric 404 can beimplemented with one or more buses or a crossbar switch.

Memory 402 and persistent storage 405 are computer readable storagemedia. In this embodiment, memory 402 includes random access memory(RAM). In general, memory 402 can include any suitable volatile ornon-volatile computer readable storage media. Cache 403 is a fast memorythat enhances the performance of processors 401 by holding recentlyaccessed data, and data near recently accessed data, from memory 402.

Program instructions and data used to practice embodiments of thepresent invention may be stored in persistent storage 405 and in memory402 for execution by one or more of the respective processors 401 viacache 403. In an embodiment, persistent storage 405 includes a magnetichard disk drive. Alternatively, or in addition to a magnetic hard diskdrive, persistent storage 405 can include a solid state hard drive, asemiconductor storage device, read-only memory (ROM), erasableprogrammable read-only memory (EPROM), flash memory, or any othercomputer readable storage media that is capable of storing programinstructions or digital information.

The media used by persistent storage 405 may also be removable. Forexample, a removable hard drive may be used for persistent storage 405.Other examples include optical and magnetic disks, thumb drives, andsmart cards that are inserted into a drive for transfer onto anothercomputer readable storage medium that is also part of persistent storage405.

Communications unit 407, in these examples, provides for communicationswith other data processing systems or devices. In these examples,communications unit 407 includes one or more network interface cards.Communications unit 407 may provide communications through the use ofeither or both physical and wireless communications links. Programinstructions and data used to practice embodiments of the presentinvention may be downloaded to persistent storage 405 throughcommunications unit 407.

I/O interface(s) 406 allows for input and output of data with otherdevices that may be connected to each computer system. For example, I/Ointerface 406 may provide a connection to external devices 408 such as akeyboard, keypad, a touch screen, and/or some other suitable inputdevice. External devices 408 can also include portable computer readablestorage media such as, for example, thumb drives, portable optical ormagnetic disks, and memory cards. Software and data used to practiceembodiments of the present invention can be stored on such portablecomputer readable storage media and can be loaded onto persistentstorage 405 via I/O interface(s) 406. I/O interface(s) 406 also connectto display 409.

Display 409 provides a mechanism to display data to a user and may be,for example, a computer monitor.

The programs described herein are identified based upon the applicationfor which they are implemented in a specific embodiment of theinvention. However, it should be appreciated that any particular programnomenclature herein is used merely for convenience, and thus theinvention should not be limited to use solely in any specificapplication identified and/or implied by such nomenclature.

The present invention may be a system, a method, and/or a computerprogram product. The computer program product may include a computerreadable storage medium (or media) having computer readable programinstructions thereon for causing a processor to carry out aspects of thepresent invention.

The computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present invention may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Smalltalk, C++ or the like, andconventional procedural programming languages, such as the “C”programming language or similar programming languages. The computerreadable program instructions may execute entirely on the user'scomputer, partly on the user's computer, as a stand-alone softwarepackage, partly on the user's computer and partly on a remote computeror entirely on the remote computer or server. In the latter scenario,the remote computer may be connected to the user's computer through anytype of network, including a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).In some embodiments, electronic circuitry including, for example,programmable logic circuitry, field-programmable gate arrays (FPGA), orprogrammable logic arrays (PLA) may execute the computer readableprogram instructions by utilizing state information of the computerreadable program instructions to personalize the electronic circuitry,in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the block may occur out of theorder noted in the figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

1-7. (canceled)
 8. A computer program product comprising: one or morecomputer readable tangible storage media and program instructions storedon at least one of the one or more storage media, the programinstructions comprising: program instructions to insert a bloom filtercreation stage after an inner data source identification stage, whereina join operation is to be performed to join an outer data source withthe inner data source; program instructions to insert a bloom filtersearch stage after an outer data source identification stage, whereineach row of data from the outer data source is searched against a bloomfilter for the inner data source during the bloom filter search stage;program instructions to initialize a read on the inner data source;program instructions to, subsequent to determining the bloom filtercreation stage is complete, initialize a read on the outer data source;and program instructions to perform the join operation at a join stage.9. The computer program product of claim 8, further comprising programinstructions, stored on the one or more computer readable storage media,which when executed by a processor, cause the processor to: create aninner data set based at least on the inner data source and the bloomfilter.
 10. The computer program product of claim 8, further comprisingprogram instructions, stored on the one or more computer readablestorage media, which when executed by a processor, cause the processorto: generate a second bloom filter based on reference data during adataset creation job; insert the second bloom filter after a data sourceduring the dataset creation job; and update a path to the second bloomfilter in an inner dataset header for the inner data source.
 11. Thecomputer program product of claim 10, further comprising programinstructions, stored on the one or more computer readable storage media,which when executed by a processor, cause the processor to: subsequentto determining one or more optimization conditions are satisfied,determine to insert the bloom filter search stage after the outer datasource identification stage.
 12. The computer program product of claim10, further comprising program instructions, stored on the one or morecomputer readable storage media, which when executed by a processor,cause the processor to: subsequent to determining one or moreoptimization conditions are not satisfied, determine to perform a joinbetween the inner data source and the outer data source without thesecond bloom filter.
 13. The computer program product of claim 11,wherein the one or more optimization conditions are selected from agroup consisting of: the join operation does not have any additivestages between the inner data source and the join, join keys passthrough unmodified from the inner data source to the join, join keyspass through unmodified from the outer data source to the join, and acost of a specific join operation without a bloom filter is greater thana processing cost of the specific join operation with the bloom filter.14. The computer program product of claim 8, further comprising programinstructions, stored on the one or more computer readable storage media,which when executed by a processor, cause the processor to: send one ormore rows from the inner data source to the join stage, wherein the oneor more rows are not searched against the bloom filter; determine thebloom filter creation stage is complete; notify the bloom filter searchstage that the bloom filter creation stage is complete; and load thebloom filter at the bloom filter search stage.
 15. A computer systemcomprising: one or more computer processors; one or more computerreadable storage media; and program instructions stored on the computerreadable storage media for execution by at least one of the one or morecomputer processors, the program instructions comprising: programinstructions to insert a bloom filter creation stage after an inner datasource identification stage, wherein a join operation is to be performedto join an outer data source with the inner data source; programinstructions to insert a bloom filter search stage after an outer datasource identification stage, wherein each row of data from the outerdata source is searched against a bloom filter for the inner data sourceduring the bloom filter search stage; program instructions to initializea read on the inner data source; program instructions to, subsequent todetermining the bloom filter creation stage is complete, initialize aread on the outer data source; and program instructions to perform thejoin operation at a join stage.
 16. The computer system of claim 15,further comprising program instructions, stored on the one or morecomputer readable storage media, which when executed by a processor,cause the processor to: create an inner data set based at least on theinner data source and the bloom filter.
 17. The computer system of claim15, further comprising program instructions, stored on the one or morecomputer readable storage media, which when executed by a processor,cause the processor to: generate a second bloom filter based onreference data during a dataset creation job; insert the second bloomfilter after a data source during the dataset creation job; and update apath to the second bloom filter in an inner dataset header for the innerdata source.
 18. The computer system of claim 17, further comprisingprogram instructions, stored on the one or more computer readablestorage media, which when executed by a processor, cause the processorto: subsequent to determining one or more optimization conditions aresatisfied, determine to insert the bloom filter search stage after theouter data source identification stage.
 19. The computer system of claim17, further comprising program instructions, stored on the one or morecomputer readable storage media, which when executed by a processor,cause the processor to: subsequent to determining one or moreoptimization conditions are not satisfied, determine to perform a joinbetween the inner data source and the outer data source without thesecond bloom filter.
 20. The computer system of claim 15, wherein theone or more optimization conditions are selected from a group consistingof: the join operation does not have any additive stages between theinner data source and the join, join keys pass through unmodified fromthe inner data source to the join, join keys pass through unmodifiedfrom the outer data source to the join, and a cost of a specific joinoperation without a bloom filter is greater than a processing cost ofthe specific join operation with the bloom filter.